Texas Instruments 990 Operation Manual page 93

JdlS\ _ _ _ _ _ _ _
~
945255-9701
Parameter default values:
If the starting memory address is not specified, a value of 0 is used.
If the ending memory address is not specified, a value of FFFF
16
is used.
If the mask parameter is not specified, a value of FF
16
is used.
Description: Each byte in the memory search range is ANDed with the mask and compared to
the desired value. The memory location and contents are printed out whenever a match is found.
After each match, the user must enter a space on the tenninal keyboard to continue the search.
If he enters a carriage return, the command tenninates.
Error messages:
DP13 The ending address is less than the starting
address. Reenter the command.
MS05 A required parameter, the desired value, is
missing. Reenter the command.
MX06 The beginning address is an invalid memory
address. Reenter the command.
Application notes: No check is made to ensure that the mask does not exclude a bit required by
the desired value, thereby making a match impossible. If the monitor is being searched, results
may not appear to be correct since the monitor is changing during the search process.
Examples:
.FB 0,20oo,0,OF
0000=0000
0000=0000
0002=0000
0002=0000
0004=0000
0004=0000
0006=0000
0006=0000
0008=0000
.FB 0,20oo,06,OF
0300=0456
0644=0556
In the first example, the high order four bits of each byte are masked so that any byte with a 0
in the low order four bits will be located. The address of the leftmost byte of each word is
printed so that if both bytes of a word are printed, an address location will be printed twice.
For example, if bytes 0004 and 0005 are printed, the address 0004 will appear twice in the
listing.
3-5'5
Digital Systems Division